
MC68F375
STATIC RANDOM ACCESS MEMORY (SRAM)
MOTOROLA
REFERENCE MANUAL
Rev. 25 June 03
11-5
the SRAM array address block. The SRAM array base address is placed on a 512, 1K,
2K or 4-Kbyte block boundary (block size greater than or equal to the size of the array).
RAMBAH and RAMBAL may only be written while the SRAM is in STOP mode STOP
= “1” and the lock bit is not set RLCK = “0”. Once the RLCK bit is set, writes will have
no effect on RAMBAH and RAMBAL. This will prevent runaway software from inad-
vertently re-mapping the array. The SRAM must be in STOP mode while RAMBAH or
RAMBAL are written this prevents inadvertent intermediate array mapping to be
acknowledged.
11.4 Operation
The SRAM module has several modes of operation. The following sections describe
SRAM module operation in each of these modes.
RAMBAH1, RAMBA1L — SRAM Base Address Registers
0xYF F844, 0xYF F846
RAMBAH2, RAMBAL2
0xYF F84C, 0xYF F84E
RAMBAH3, RAMBAL3
0xYF F854, 0xYF F856
RAMBAH4, RAMBAL4
0xYF F85C, 0xYF F85E
RAMBAH, RAM1BAL
0xYF FB04, 0xYF FB06
MSB
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
LSB
16
RAMBAH
RESET:
0
MSB
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
0
RAMBAL
RESERVED
RESET:
0
Table 11-3 RAMBAH, RAMBAL Bit Settings
Bit(s)
Name
Description
31:16
RAMBAH
Array base address high. With STOP asserted the base Address field of RAMBAH may be
changed so that the array may be placed at the desired address in the memory map. This must
be done by a supervisor program since the register is in supervisor data space. To lock the base
address field, RLCK in the RAMMCR should be set. This will prevent the base address field from
being changed until the next master reset.
15:9
RAMBAL
Array base address low. With STOP asserted the base Address field of RAMBAL may be
changed so that the array may be placed at the desired address in the memory map. This must
be done by a supervisor program since the register is in supervisor data space. To lock the base
address field, RLCK RAMMCR should be set. This will prevent the base address field from being
changed until the next master reset.
8:0
—
Reserved
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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